1. Field of the Invention
The present invention relates to a computer system with a simplified power control function, and more particularly, to a computer system having a power supply section for starting a supply of a source voltage to the main computer block therein by means of a reset switch provided for resetting the main computer block without the use of a power switch and for interrupting the supply of the source voltage by either a combination of specific key input signals or by programming.
2. Description of the Related Art
As well known in the art, computer systems may embody several sorts of power control systems: a power control system operated by means of a power switch, a power control system which operates in response to a combination of specific key input signals from a keyboard, a power control system operated by means of a remote control, and a power control system capable of restarting the supply of a source voltage to the main computer block in response to a specific key input signal from the keyboard.
The above-noted power control systems may be selectively adapted to a personal computer system, while in an upgraded computer system, several power control systems may be embodied.
First, to supply a source voltage to the main computer block by means of a power switch, two methods have been utilized, one of which is to supply the source voltage by means of a power switch provided on an AC (Alternating Current) line and the other is to supply the source voltage upon the detection of the operation of a soft switch (e.g., any key on the keyboard), which is operated with a DC (Direct Current) voltage supplied from a power supply contained within the computer system.
The former method is utilized to control electrical connection/non-connection (ON/OFF) of the AC line, which is connected to the power supply in the computer system, by using a physical switch. This method can cause circuit damage to an SMPS (switching mode power supply) which is caused by a leakage current occurring upon starting or cutting off a source voltage to the main computer block in response to the ON/OFF connection of the AC line.
Also, the latter method is utilized to cut off a source voltage to the main computer block by using a soft switch, which is operated with a DC voltage of a power supply contained therein. In this method, an AC voltage supplied through the AC line to the power supply is not cut off even if a source voltage to the main computer block is cut off by using the soft switch. But this method has a disadvantage in that the supply of the source voltage to the main computer block may be cut off by a user's mistake or intention by another person while the computer system is operating because of the sensitive operation of the soft switch, resulting in a poor protection of the computer system.
In order to solve the above described problem of the power control system operated by means of the ON/OFF connection of a power switch, a method for controlling the power supply in accordance with a combination of specific key input signals has been proposed. In this method, an SMPS contained within the computer system must continue to provide a standby current to a keyboard controller besides a keyboard in order that the keyboard controller can detect the combination of the specific key input signals supplied from the keyboard. When the combination thereof is detected, the SMPS starts to supply the source voltage to the main computer block. In this method, the combination of the specific key input signals or the power switch is also used to cut off the supply of the source voltage to the main computer block. This method has a advantage of a good protection of the computer system operation, as compared with the method using the soft switch, but a disadvantage of a large current-consumption because a source voltage must always be supplied for the keyboard operation. Also, when that the keyboard is separated from the main computer block, it is impossible to control the supply or the cut-off of the source voltage to the main computer block.
Additionally, the remote control method must utilize a receiver for receiving a remote control signal from a transmitter. In this method, the stand-by current from the SMPS in the computer system must be continuously supplied for the receiver in order that the receiver can receive and detect the remote control signal. If the detected signal is related to the supply control of the source voltage, the source voltage is supplied for the main computer block. In this method, since the source voltage is always supplied for the receiver so that a processor and a logic circuit therein may be operated, power is continuously consumed. The receiver can also be affected by other remote control devices used in other electrical products. This method has a disadvantage in that an additional power switch must be embodied in the computer system to control the supply or the cut-off of a source voltage thereto.
Finally, according to the method for restarting the supply of the source voltage to the main computer block in accordance with the specific key input signal of the keyboard, a data line of the keyboard is activated by soft-touching of the keyboard and then the power is supplied for the main computer block. Since the computer system detects only whether the data line is activated during the cut off of the source voltage, an undesirable source voltage can be supplied thereto when the keyboard is touched by mistake or an intention by another person. This method also has a disadvantage in that it is necessary for an additional function to cut off the supply of the source voltage. Particularly, the computer system in which the method is embodied must be operated in order that a power supply, therein is in a wake-up state during the standby-mode or hibernation mode.
Earlier computer systems have a main computer body (i.e., a main computer block), input devices such as a keyboard and a mouse and output devices such as a monitor and speakers. The speakers can be built into the main computer body or separately provided. Several switches, such as a power switch, a built-in microphone ON/OFF switch, and a reset switch, etc., are installed on a front panel of the main computer body to control several functions of the computer system. The reset switch is used for resetting and booting the computer system and the power switch is used for controlling the supply and the cut-off of the source voltage to the main computer block.
The AC source voltage is supplied through power lines to an SMPS of the computer body via the power switch when the power switch is closed.
A reset generator, included in the main computer body, generates a reset signal for resetting the main computer block upon the operation of the reset switch. When the reset signal is generated by the reset signal generator, a booting program is performed in the main computer block to initialize and restart the operation of the main computer block. The reset signal generator may be composed of two capacitors connected in parallel across the terminals of the reset switch, a resistor connected to a DC voltage source and with the one of the two capacitors and an inverter connected to the junction of the resistor and the two capacitors. The reset switch has two terminals, one of which is grounded and the other which is connected to the junction of the capacitors and the resistor. Accordingly, when the reset switch is closed, an integrated signal is generated by an integrator circuit composed of the resistor and the capacitors, the integrated signal then being changed into a pulse signal by means of the inverter. This pulse signal is used as the reset signal.
Since the computer system has the reset switch for initializing the operation thereof in addition to the power switch for controlling the supply of source voltage to the power supply therein, the above described problems may occur.
The Clark et al. patent, U.S. Pat. No. 5,513,359, entitled Desktop Computer Having A Single-Switch Suspend/Resume Function, discloses a computer system in which a momentary pushbutton switch controls a state of the computer between a normal operating state, a suspend state, and an off state.
The White et al. patent, U.S. Pat. No. 5,410,713, entitled Power-Management System For A Computer, discloses a power management system for a computer in which the ON/OFF control of the computer is controlled by a switch which does not control the AC power but rather provides a signal to control the operation of a switchable power supply.
The Inoue, Folkes et al., and Conary patents, U.S. Pat. Nos. 5,008,846, 5,570,050, and 5,543,741, respectively entitled Power And signal Supply Control Device, Zero Standby Current Power-Up Reset Circuit, and Reset Circuit For Generating Reset Pulse Over An Interval Of Reduced Voltage Supply, each disclose computer systems in which a reset signal is automatically generated upon the power being supplied to the computer system.
The following additional patents each disclose features in common with the present invention but are not believed to be as pertinent as the patents discussed above:
U.S. Pat. No. 5,543,741 to Purits, entitled Reset Circuit For Generating Reset Pulse Over An Interval Of Reduced Voltage Supply, U.S. Pat. No. 4,614,880 to Go et al., entitled Power Supply Circuitry For A Microcomputer System, U.S. Pat. No. 5,237,698 to Ohmae, entitled Microcomputer, U.S. Pat. No. 5,442,310 to Bazes, entitled Circuitry And Method For Reset Discrimination, and U.S. Pat. No. 5,513,358 to Lundberg et al., entitled Method And Apparatus For Power-Up State Initialization In A Data Processing System.
None of the cited patents teaches or suggests the specifically recited combination of the features of the present invention.